The present invention relates to a novel slip joint for an endotracheal tube, and more particular to a slip joint of endotracheal tube, by which the determination of the location of the tip of a catheter inserted into the bronchi and of a pathological condition in the thorax by means of a sound signal sent into the catheter, the suction of secretions in the trachea and bronchi and the monitoring of a gas in the lung can be conducted with ventilating.
In the field of clinical medicine, particularly in anaesthesia or artificial ventilation of patients with respiratory failure, it is very important for supplying a sufficient amount of oxygen to the lung to remove secretions such as sputum in the trachea and bronchi.
Hitherto, the removal of secretions in the trachea and bronchi by suction during anesthesia or artificial ventilation has been generally conducted in a manner as shown in FIGS. 1 to 2. FIG. 1 is an illustrative view showing the state that anaesthesia or artificial ventilation is conducted, and FIG. 2 is an illustrative view showing the state that the removal of secretions is conducted. In FIGS. 1 and 2, reference numeral 1 is trachea, reference numeral 2 is right bronchus, and reference numeral 3 is left bronchus. As shown in FIG. 1, an endotracheal tube 4 (the term "endotracheal tube" as used herein comprehending a tracheostomy cannula) is inserted into the trachea 1, and the proximal end of the endotracheal tube 4 is connected to a ventilator or anaesthetic machine 9 through a slip joint 5, an angle adaptor 6, a Y-shaped adaptor 7 and corrugate tubes 8a and 8b. The tube 8a is inspiratory tube and the tube 8b is expiratory tube. General anaesthesia or artificial ventilation is conducted in such a state. The suction of secretions is then conducted, as shown in FIG. 2, by detaching the angle adaptor 6 from the slip joint 5 to cut off the communication between the endotracheal tube 4 and the ventilator or anaesthetic machine 9, inserting a catheter 10 from the opening end of the slip joint 5 into the bronchus through the endotracheal tube 4, and connecting the proximal end of the catheter 10 to a suitable vacuum source 11.
Like this, the suction of secretions in the trachea and bronchi during anaesthesia or artificial ventilation has hitherto been conducted with disconnection of the ventilator or anaesthetic machine, that is to say, in the state that the ventilation is interrupted. Spontaneous respiration of a patient is often arrested by dosage of a muscle relaxant or other various drugs in order to conform the respiration of the patient with a ventilator during artificial ventilation and general anaesthesia or to make operative procedures easy. However, in such a case, disconnection of the ventilator or anaesthetic machine may plunge the patient into apnoea. When secretions in the trachea and bronchi is aspirated under such an apnoeic condition, a mixed gas such as O.sub.2 +N.sub.2 or O.sub.2 +N.sub.2 O in the lung is almost removed and the patient is plunged into hypoxic condition. Also, in case of respiratory care of a patient in a bad condition who raises a great deal of secretions, aspiration must be frequently done and it is reported that the frequent aspiration may cause bradycardia, tachycardia, various types of arrhythmia and cardiac arrest in hypoxic condition and is dangerous. Further, it is reported that in case of a patient with respiratory failure, particularly a newborn or infant of small lung capacity, all the gas in the lung is aspirated upon aspiration of secretions and the lung collapse (atelectasis) is caused. For these reasons, at present it is recommended to conduct the aspiration in such a manner as sufficiently ventilating the lung with 100% oxygen prior to aspiration, conducting aspiration procedure in as short time as possible, for instance, in 10 to 15 seconds, and sufficiently ventilating the lung with 100% oxygen immediately after aspiration, but this manner is troublesome.
Since the suction of secretions with the interruption of ventilation causes various troubles as stated above, it is also proposed to conduct the suction in a manner in which the angle adaptor is provided with a hole for inserting a suction catheter, and the catheter is inserted through the hole of the angle adaptor and the suction is conducted in the state that the endotracheal tube is communicated with the ventilator or anaesthetic machine. However, since the insertion hole is made larger than the outer diameter of the catheter in order to make the insertion of catheter easy, an inspiratory gas such as oxygen is leaked out from a gap between the catheter and the insertion hole. Therefore, it is impossible to ventilate the lung during the insertion of catheter and to aspirate secretions while supplying a sufficient amount of oxygen to a patient.
Accordingly, there is desired the development of a device enabling to aspirate secretions while ventilating and supplying sufficient oxygen to patients.
The present inventor previously developed a device capable of easily, exactly and safely determining the position of the distal end of a catheter inserted into the bronchus by sending a sound signal into the inserted catheter and receiving the sound signal sent forth from the distal end of the catheter, and thereby the selective suction of the left or right bronchus is possible, and a device capable of easily, exactly and safely determining the pathological condition in the thorax such as pulmonary edema, pleural effusion, hemothorax, pyothorax, pneumothorax or neoplasm of the lung by utilizing that the sound signal sent force from the tip of the catheter is attenuated until it reaches a sound signal receiver through the chest wall and the degree of the attenuation varies largely depending on the pathological condition. It is also desirable that the determination of the position of the tip of catheter and determination of the pathological condition in the thorax by such a device are conducted while ventilating the lung.
Further, in case of artificial ventilation over a long term, gas (oxygen and carbon dioxide) in the lung is continuously collected by a catheter of smaller calibre inserted into the lung than a suction catheter and the composition of the gas is monitored to determine whether the artificial ventilation is correctly conducted. In that case, it is also desirable to collect the gas while ventilating the lung.